A trocar sleeve of this kind is known from EP 0 484 725 A.
Trocar sleeves are used in minimally invasive procedures to gain access to an internal cavity of the body. In laparoscopy, this is the abdominal cavity. For this purpose, the trocar sleeve has a hollow shaft which, when the trocar sleeve is applied, is placed over an incision in the abdominal wall and pushed through the latter. Thereafter, the distal end of the shaft protrudes into the abdominal cavity, while the proximal end protrudes from the upper face of the abdominal wall
In many embodiments, the trocar sleeve is applied by pushing a trocar mandrel into the hollow shaft, said trocar mandrel having a distal tip which extends beyond the distal end of the trocar sleeve. This combination of trocar sleeve and trocar mandrel, i.e. the actual trocar, is pushed through the abdominal wall. Thereafter, the trocar mandrel is withdrawn, such that suitable instruments can then be inserted through the hollow shaft into the body cavity.
In many trocar sleeves, a helically extending external thread is present on and rises from the outer face of the hollow shaft. The trocar sleeve can be screwed in or out through the tissue via this thread.
Particularly in laparoscopy procedures, it is desirable to inflate the internal cavity of the body, i.e. the abdominal cavity, with an insufflation gas in order to provide a better view of the interior. For this purpose, a housing provided with a seal, and with an attachment for delivery of an insufflation gas, is mounted in most cases on the proximal end of the shaft of the trocar sleeve. In many designs, further attachments can be provided on the trocar housing, for example in order to deliver and remove irrigation liquids. In practical use, corresponding hose lines are then attached, as a result of which the trocar sleeve becomes rather top-heavy. This poses the risk of the trocar sleeve changing its position during use, for example by moving in the proximal direction or tilting. It would be fatal if the trocar sleeve were to accidentally slide out of the body during an endoscopy procedure.
In some embodiments, the hollow shaft is made from a flexible material, mostly a plastic material. The clear internal diameter of the hollow shaft defines the maximum diameter of an instrument that can be guided through the trocar sleeve. In many surgical techniques, it is necessary to insert instruments that are curved or are bent sideways. In the case of rigid trocar sleeves, for example those made of steel, such instruments cannot be guided through, or they can be guided through only with deformation. In these cases, flexible trocar sleeves are used. The tubular body of the hollow shaft is made from an elastic polymer that is able to adapt to the bending of the surgical instruments that are passed through. When bent instruments are guided through a trocar sleeve, there is a danger of the latter being shifted.
Moreover, the plastic materials that are used generally have lower coefficients of friction than the materials of rigid trocar sleeves, such that there is additionally the danger of a fitted trocar sleeve shifting.
It is an object of the present invention is to develop a trocar sleeve that can be inserted with minimal trauma into a cavity of the body and that is secured at least against withdrawal from the body.